Sensor mounted flexible guidewire

ABSTRACT

A medical device comprising a corewire, sensor core, and coupler is presented. A portion of the corewire is disposed within a first end of the coupler, and a portion of the sensor core is disposed within a second end. Alternatively, the device comprises a corewire and a sensor assembly comprising a sensor core having first and second ends and a bore in the first end. A portion of the corewire is disposed within the bore. A method of manufacture comprises providing a corewire, sensor core, and coupler. The method further comprises inserting a portion of the corewire into a first end of the coupler, and a portion of the sensor core into a second end. Alternatively, the method comprises providing a sensor core having first and second ends, and a corewire. The method further comprises forming a bore in the first end, and inserting the corewire into the bore.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/357,971 entitled “Sensor Mounted Flexible Guidewire” filedJan. 22, 2009, the entire disclosure of which is incorporated herein byreference. U.S. patent application Ser. No. 12/357,971 in turn claimsthe benefit of U.S. Provisional Patent Application No. 61/023,007 filedJan. 23, 2008, and U.S. Provisional Patent Application Ser. No.61/028,665 filed Feb. 14, 2008, both of which are hereby incorporated byreference in their entireties.

BACKGROUND OF THE INVENTION

a. Field of the Invention

The disclosed technique relates to guidewires, in general, and tomethods and systems for including electronic components in guidewiresand for making guidewires more flexible, in particular.

b. Background Art

Guidewires are employed in noninvasive operations to enable thephysician to navigate to a desired location within the lumen of the bodyof the patient, and then insert the catheter to the desired locationwith the aid of the guidewire. Such guidewires are known in the art. Onetype of guidewire includes a sensor at the tip thereof, which isconnected to an electronic unit, with a pair of wires which pass througha lumen within the guidewire. The guidewire includes a coil in front ofthe sensor to enable maneuverability. Another type of guidewire includesa sensor at the tip thereof, which is connected to the electronic unitwith a pair of wires which pass through the lumen within the guidewire.This guidewire is devoid of a flexible element to providemaneuverability.

U.S. Pat. No. Re. 35,648 issued to Tenerz et al., and entitled “SensorGuide Construction and Use Thereof”, is directed to a guidewire whichincludes a thin outer tube, an arched tip, a radiopaque coil, a solidmetal wire, a sensor element, and a signal transmitting cable. Theradiopaque coil is welded to the arched tip. The solid metal wire isformed like a thin conical tip, and it is located within the arched tipand the radiopaque coil. The solid metal wire successively tapers towardthe arched tip. At the point where the solid metal wire joins theradiopaque coil, the thin outer tube commences. The signal transmittingcable extends from the sensor element to an electronic unit through anair channel within the thin outer tube.

U.S. Pat. No. 4,873,986 issued to Wallace, and entitled “DisposableApparatus for Monitoring Intrauterine Pressure and Fetal Heart Rate”, isdirected to an apparatus to monitor the fetal condition during labor andchildbirth. The apparatus includes a cable, a pressure transducer, aplug, and a pair of wires. The pressure transducer is located within theleading edge of the cable. The plug is located at a proximal end of thecable. The signals from the pressure transducer are conveyed to the plugby way of the pair of wires, which pass through a vent channel withinthe cable.

U.S. Pat. No. 6,428,489 issued to Jacobsen et al and entitled “GuidwireSystem”, is directed to a catheter guidewire which includes an elongatesolid body. Around this elongated solid body, a catheter is guidedtoward a target location in the vasculature system of a body. Theelongate body includes a proximal end and a distal end, with the distalend being curved. Cuts are formed by either saw-cutting, laser cuttingor etching at spaced-apart locations along the length of the body,thereby increasing the lateral flexibility of the guidewire. Integralbeams are also formed within the body to maintain its torsionalstrength. The relative location and size of cuts and beams may beselectively adjusted, thereby determining the direction and degree offlexure, and the change in torsional stiffness relative to flexibility.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a medical device, such as, forexample, a guidewire. In an exemplary embodiment, the medical device, inaccordance with the present teachings, comprises a corewire, a sensorcore, and a coupler. The coupler has a first end and a second end. Aportion of the corewire is disposed within the first end of the coupler,and a portion of the sensor core is disposed within the second end ofthe coupler. The coupler is operative to couple the corewire with thesensor core.

In another exemplary embodiment, the medical device comprises a corewirehaving a proximal end and a distal end, and a sensor assembly comprisinga sensor core. The sensor core comprises a first end, a second end, anda bore in the first end. A portion of the corewire at the distal endthereof is disposed within the bore in the first end of the sensor core.

In accordance with another aspect of the invention, a method ofmanufacturing a medical device, such as, for example, a guidewire, isprovided. In an exemplary embodiment, the method, in accordance with thepresent teachings, comprises the steps of providing a corewire,providing a sensor core configured to have a sensor mounted thereon, andproviding a coupler configured to couple the corewire with the sensorcore. The method further comprises inserting a portion of the corewireinto a first end of the coupler. The method still further comprisesinserting a portion of the sensor core into a second end of the coupler.

In another exemplary embodiment, the method comprises the steps ofproviding a sensor core configured to have a sensor mounted thereon andhaving a first end and a second end opposite the first end, andproviding a corewire. The method further comprises the steps of forminga bore in the first end of the sensor core, and inserting a portion ofthe corewire into the bore.

The foregoing and other aspects, features, details, utilities, andadvantages of the present invention will be apparent from reading thefollowing description and claims, and from reviewing the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic illustration of a guidewire in a cross-sectionalview, constructed and operative in accordance with an embodiment of thedisclosed technique;

FIG. 1B is a schematic illustration showing the flexibility of aguidewire, constructed and operative in accordance with anotherembodiment of the disclosed technique;

FIG. 2 is a schematic illustration of another guidewire, in across-sectional view, constructed and operative in accordance with afurther embodiment of the disclosed technique;

FIG. 3A is a perspective illustration of a guidewire having a tip whichexhibits substantially increased flexibility, constructed and operativein accordance with another embodiment of the disclosed technique;

FIG. 3B is an orthographic illustration, in top view, of the guidewireof FIG. 3A, constructed and operative in accordance with a furtherembodiment of the disclosed technique;

FIG. 3C is an orthographic illustration, in front view, of the guidewireof FIG. 3A, constructed and operative in accordance with anotherembodiment of the disclosed technique;

FIG. 4 is a schematic illustration showing the procedures executed informing the guidewire of FIG. 3A, constructed and operative inaccordance with a further embodiment of the disclosed technique;

FIG. 5A is a perspective illustration of another guidewire having asubstantially flexible tip, constructed and operative in accordance withanother embodiment of the disclosed technique;

FIG. 5B is an orthographic illustration, in top view, of the guidewireof FIG. 5A, constructed and operative in accordance with a furtherembodiment of the disclosed technique;

FIG. 5C is an orthographic illustration, in front view, of the guidewireof FIG. 5A, also showing cross-sections of the guidewire, constructedand operative in accordance with another embodiment of the disclosedtechnique;

FIG. 6 is a schematic illustration showing the procedures executed informing the guidewire of FIG. 5A, constructed and operative inaccordance with a further embodiment of the disclosed technique;

FIG. 7, is a schematic illustration of a cross sectional view of aguidewire, constructed and operative in accordance with anotherembodiment of the disclosed technique;

FIG. 8A is a schematic perspective exploded illustration of a guidewire,constructed and operative in accordance with a further embodiment of thedisclosed technique;

FIG. 8B is a schematic perspective illustration of the guidewireillustrated in FIG. 8A at an intermediate stage of assembly;

FIG. 8C is a schematic illustration of a cross-sectional view of theguidewire illustrated in FIGS. 8A and 8B at an intermediate stage ofassembly;

FIG. 8D is a schematic perspective illustration of the guidewireillustrated in FIGS. 8A-8C at an intermediate stage of assembly;

FIG. 8E is a schematic illustration of a cross-sectional view of theguidewire illustrated in FIGS. 8A-8D at a near final stage of assembly;

FIG. 9A is a schematic perspective exploded illustration of a guidewireconstructed and operative in accordance with a further embodiment of thedisclosed technique;

FIG. 9B is a schematic perspective illustration of the guidewireillustrated in FIG. 9A at an intermediate stage of assembly;

FIG. 10 is a flow chart diagram illustrating an exemplary embodiment ofa method of manufacturing the guidewires illustrated in FIGS. 8A-9B inaccordance with the present teachings.

FIG. 11A is schematic perspective exploded illustration of a portion ofa guidewire constructed and operative in accordance with yet a furtherembodiment of the disclosed technique;

FIG. 11B is a schematic perspective illustration of the guidewireillustrated in FIG. 11A at an intermediate stage of assembly;

FIG. 11C is a schematic illustration of another exemplary embodiment ofthe guidewire illustrated in FIGS. 11A and 11B at an intermediate stageof assembly;

FIG. 11D is cross-sectional view of the guidewire illustrated in FIGS.11A and 11B at a near final stage of assembly; and

FIG. 12 is a flow chart diagram illustrating an exemplary embodiment ofa method of manufacturing the guidewires illustrated in FIGS. 11A-11D inaccordance with the present teachings.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The disclosed technique overcomes the disadvantages of the prior art byproviding a novel guidewire design and forming technique. The noveldesign enables electronic components, such as sensors and electricalwires, to be placed within the guidewire, in particular in the tip ofthe guidewire. Such electronic components allow for scalar and vectorvalues to be measured at the guidewire's tip. The design also increasesthe flexibility of the guidewire, in particular at its distal end. Thenovel forming technique enables a guidewire to be formed having asubstantially increased level of flexibility over prior art guidewires.Throughout the description, the guidewire of the disclosed technique isdescribed in reference to medical guidewires. It is noted that the terms“position” and “location” are used interchangeably throughout thedescription and in general refer to the three dimension location of anobject in a predefined coordinate system.

Reference is now made to FIG. 1A, which is a schematic illustration of aguidewire, in a cross-sectional view, generally referenced 100,constructed and operative in accordance with an embodiment of thedisclosed technique. FIG. 1A substantially shows the inside of guidewire100. Guidewire 100 includes a hollow tube 105, a plug 110, a sensor 112,a twisted pair of wires 114 and a tubular spring 118. Guidewire 100 canbe coupled with an interconnect 116. In general, guidewire 100 includestwo sections, a distal section 102 and a proximal section 104. Distalsection 102 refers to the distal end of guidewire 100, the end ofguidewire 100 which is distant from interconnect 116. Proximal section104 refers to the proximal end of guidewire 100, the end of guidewire100 which is nearest to interconnect 116. In FIG. 1A, distal section 102and proximal section 104 are separated by a set of lines 103. Hollowtube 105 includes a walled section 106 and a hollow section 108. Hollowsection 108 can also be referred to as a cavity or a lumen. Twisted pairof wires 114, referred to herein as twisted pair 114, are coupled withsensor 112 and with interconnect 116. Plug 110 is coupled with thedistal tip of guidewire 100. As explained in further detail below,tubular spring 118 is placed around a particular section of distalsection 102 of guidewire 100. Sensor 112 and twisted pair of wires 114are located inside hollow tube 105 in hollow section 108.

Sensor 112 is sensor capable of measuring scalar values such as pressureand temperature as well as vector values such as position andorientation of a magnetic field. For example, sensor 112 is a coilsensor capable of measuring the strength and orientation of a magneticfield. In general, micro-coil sensor can have a thickness on the orderof a few hundred micrometers, such as 250 μm. Twisted pair 114 includeswires capable of transferring electrical signals from sensor 112 tointerconnect 116. The wires of twisted pair 114 can have a thickness onthe order of tens of micrometers, for example, between 10-25 μm. Plug110 can be made of metal or of a polymer bonded into guidewire 100. Plug110 may further be made of bonding material shaped into a hemisphericalshape. Plug 110 is coupled to the distal tip of guidewire 100 by gluing,bonding, welding or soldering. Plug 110 can also just be glue. Tubularspring 118 is a tube exhibiting lateral flexibility (i.e., perpendicularto the central axis of the tube). Tubular spring 118 is, for example, ametal (e.g., stainless steel, platinum, iridium, nitinol) coil spring aflexible polymer tube or a braided or coiled plastic tube. Tubularspring 118 maintains the outer diameter of guidewire 100 over the lengththereof (i.e., typically tubular spring 118 maintains diameter 132).Furthermore, tubular spring supports compressive loads and resistsbuckling of the section 122 without substantially increasing torsionaland bending stiffness. Tubular spring 118 can also be made of aradiopaque material, which prevents radiation from passing therethrough. Interconnect 116 enables guidewire 100, and in particulartwisted pair of wires 114, to be coupled with other devices, such as acomputer, a power source, a device measuring magnetic field strength andorientation and the like. Guidewire 100 may be further covered by a thinelastic polymer layer (not shown) over sections 120 and 122. Thispolymer layer is typically a heat shrink tube of a few micronsthickness, which provides a slick, smooth and lubricious surface.

As mentioned above, guidewire 100 can be used to measure various scalarand vector values and in particular scalar and vector values as detectedand determined at the distal tip of guidewire 100. When sensor 112 is amicro-coil sensor, sensor 112 and located in the distal tip of guidewire100, guidewire 100 can be used to determine the strength and orientationof a magnetic field at the distal tip of guidewire 100, which in turncan be used to determine the position and orientation of the distal tipof guidewire 100. For example, if guidewire 100 is used in a medicalapplication, where guidewire 100 is inserted inside a living object,such as a human or an animal, then guidewire 100 can determine theposition and orientation of its distal tip based on the measurements ofsensor 112. In general, in such an application a magnetic field isgenerated in the vicinity of the living object and sensor 112 is capableof measuring the magnetic field strength and orientation. Thesemeasurements are provided as electrical signals from sensor 112 totwisted pair 114 which in turn provide the electrical signals tointerconnect 116. Interconnect 116 can be coupled with a computercapable of determining the position and orientation of the micro-coilsensor based on the electrical signals received. Since sensor 112 islocated in the distal tip of guidewire 100, the position and orientationof sensor 112 is substantially the position and orientation of thedistal tip of guidewire 100.

In position sensing applications involving magnetic fields, magneticinterference, such as induced electrical currents, can cause errors andbiases in the electrical signals provided from twisted pair 114 tointerconnect 116. In order to reduce the amount of magneticinterference, the wires located inside hollow section 108 are generallytwisted, which reduces the amount of induced electrical current in thewires due to the presence of a magnetic field. Furthermore, tubularspring 118 may be made of a radiopaque material such that it can be seenon an X-ray. If guidewire 100 is used in a medical application where itis inserted inside a living object, and tubular spring 118 is made of aradiopaque material, then, tubular spring 118 will appear on an X-ray ofthe living object and therefore, distal section 102 of the guidewirewill also appear on the X-ray image. This information can be used alongwith the measurements of sensor 112 to enhance the determination of theposition and orientation of the distal tip of guidewire 100.

As described in more detail in FIG. 1B, distal section 102 of guidewire100 is flexible which provides increased maneuverability to guidewire100. Increased maneuverability enables a user of guidewire 100 to moreeasily maneuver the guidewire when it is inserted into a living object.The flexibility of the distal end of guidewire 100 is achieved bychanging the outer diameter of walled section 106 of hollow tube 105 asfurther described. In general, to increase the flexibility of hollowtube 105, it is required to reduce the outer diameter thereof, whilemaintaining the ability of hollow tube 105 to withstand compressiveloads, buckling and kinking. Hollow tube 105 is generally made of ametal, such as stainless steel or nitinol. In the embodiment shown inFIG. 1A, hollow tube 105 is made from a single piece of metal. The factthat hollow tube 105 is made of metal provides twisted pair 114 withshielding from electromagnetic interferences. Thus, twisted pair 114 maybe an unshielded twisted pair, thereby reduce the thickness of twistedpair 114 to the order of tens of micrometers. Hollow tube 105 can bedefined by the diameter of hollow section 108, known as the innerdiameter, as well by the diameter of walled section 106, known as theouter diameter. In FIG. 1A, both the inner and outer diameters of hollowtube 105 are measured from a centerline 150. The inner diameter, asshown by an arrow 134, is substantially on the order of hundreds ofmicrometers, such as 100 μm. In cardio-logical applications, the inner,diameter shown by an arrow 134, is substantially on the order of tens ofmicrometers. As can be seen in FIG. 1A, the inner diameter of hollowtube 105 does not change along the length of guidewire 100. The outerdiameter, as can be seen in FIG. 1A, changes along the length ofguidewire 100, as shown by an arrow 132, an arrow 136 and an arrow 138.Hollow tube 105 can also be described in terms of the thickness ofwalled section 106. For example, as the outer diameter of hollow tube105 reduces, the thickness of walled section 106 also reduces, as shownby an arrow 140, an arrow 142 and an arrow 144. The outer diameter shownby arrow 132 represents the original diameter of hollow tube 105, whichis substantially on the order of hundreds of micrometers, such as 350μm. In general, the outer diameter of distal section 102 of guidewire100 is reduced, in a step-like, gradual manner, using various techniquessuch as grinding and drawing.

As can be seen in FIG. 1A, a first section 130 represents the shape ofhollow tube 105 over a majority of the length of guidewire 100. Recallthat lines 103 represent a break between the distal and proximalsections of guidewire 100 wherein the dimensions of the guidewire do notchange and remain fixed. Guidewire 100 can measure, for example up to200 centimeters. Section 130 can measure, for example, up to 160centimeters. Adjacent to first section 130 is a first transition section128, where the outer diameter of walled section 106 is gradually tapereduntil a first predetermined reduced outer diameter, such as the outerdiameter defined by arrow 136. Adjacent to first transition section 128is a second section 126, where the dimensions of the guidewire do notchange and remain fixed. Adjacent to second section 126 is a secondtransition section 124, where the outer diameter of walled section 106is gradually tapered until a second predetermined reduced outerdiameter, such as the outer diameter defined by arrow 138. Adjacent tosecond transition section 124 is a third section, which is subdividedinto a floppy section 122 and a sensor housing section 120. This thirdsection is characterized in that the thickness of walled section 106does not change and remains fixed as can be seen from arrow 144 and anarrow 146, both of which are the same size. In general, the length ofthe distal section, over which the diameter of the guidewire is reduced(i.e., sections 120, 122, 124, 126 and 128) is between 20-40centimeters.

In general, the thickness of walled section 106 in the third section issubstantially on the order of tens of micrometers, such as 25 μm,meaning that the outer diameter in floppy section 122, as shown by anarrow 138, is substantially on the order of hundreds of micrometers,such as 125 μm. At an outer diameter of hundreds of micrometers, floppysection 122 and sensor housing section 120 of guidewire 100 haveincreased flexibility and maneuverability. In general, floppy section122 can typically measure between 40 mm to 300 mm. As floppy section 122is flexible and not rigid, tubular spring 118 is placed around thissection to strengthen the distal tip of guidewire 100 while at the sametime not reducing its flexibility. Sensor housing section 120, whichinitially had an inner diameter similar to the inner diameter of floppysection 122, as shown by arrow 134, is enlarged to an inner diameter asshown by an arrow 148 such that sensor 112 can be inserted into sensorhousing section 120. When sensor 112 is a micro-coil sensor, thethickness of sensor 112 may be on the order of hundreds of micrometers,such as 250 μm, meaning that the inner diameter of the distal tip ofguidewire 100, in this example, is substantially doubled, fromapproximately 100 μm to 200 μm. The outer diameter of sensor housingsection 120 can be increased by drawing the distal tip of guidewire 100over a mandrel. In general, sensor housing section can typically measurebetween 1 mm and 5 mm. It is noted that the dimensions of the generalconfiguration, as shown in FIG. 1A, can be changed and varied so as toprovide increased flexibility, pushability, torque response and tactilefeel. For example, more transitions sections or fewer transitionsections could have been present in guidewire 100. The number oftransition sections, as well as their respective length can bedetermined and altered by one skilled in the art according to the needsof a particular application, user or both. Alternatively, the outerdiameter of guidewire 100 may decrease continuously, either linearly oraccording to a determined function (e.g., the outer diameter maydecrease exponentially).

Reference is now made to FIG. 1B, which is a schematic illustrationshowing the flexibility of a guidewire, generally referenced 170,constructed and operative in accordance with another embodiment of thedisclosed technique. Guidewire 170 is substantially similar to guidewire100 (FIG. 1A). Guidewire 170 is constructed from a hollow tube 172. Asin FIG. 1A, the distal and proximal sections of guidewire 170 areseparated by a set of lines 173. As in FIG. 1A, hollow tube 172 ischaracterized by an outer diameter and an inner diameter, whereby theouter diameter of the hollow tube is reduced at the distal end of theguidewire. Guidewire 170 includes a first section 174, which representsthe shape of hollow tube 172 over a majority of the length of guidewire170. In first section 174, the dimensions of the guidewire do not changeand remain fixed. Adjacent to first section 174 is a first transitionsection 176, where the outer diameter of hollow tube 172 is graduallytapered until a first predetermined reduced outer diameter. Adjacent tofirst transition section 176 is a second section 178, where thedimensions of the guidewire do not change and remain fixed. Adjacent tosecond section 178 is a second transition section 180, where the outerdiameter of hollow tube 172 is gradually tapered until a secondpredetermined reduced outer diameter. Adjacent to second transitionsection 172 is a third section, which is subdivided into a floppysection 182A and a sensor housing section 184A. This third section ischaracterized in that the thickness of the walled section of hollow tube172 (not shown) does not change and remains fixed.

In FIG. 1B, a tubular spring 186A is placed around floppy section 182Ain order to strengthen the third section while also maintaining theflexibility of this section. Two additional positions of the floppysection and the sensor housing section of guidewire 170 are shown usingbroken lines, demonstrating the flexible nature of the third section. Ina first additional position, shown by a floppy section 182B, a sensorhousing section 184B and a tubular spring 186B, the distal end ofguidewire 170 is displaced by an amount shown as an arrow 188A. In asecond additional position, shown by a floppy section 182C, a sensorhousing section 184C and a tubular spring 186C, the distal end ofguidewire 170 is displaced by an amount shown as an arrow 188B. Duereduced outer diameter of the floppy section and the sensor housingsection of guidewire 170, the two additional positions shown in FIG. 1Bare possible. Also, because the tubular spring applies a restoring forcewhen the distal end of guidewire 170 is in either of the two additionalpositions shown in FIG. 1B, the distal end of guidewire 170 maintains acertain amount of rigidness as the tubular spring is always trying tomaintain the floppy section in the position of floppy section 182A.

Reference is now made to FIG. 2, which is a schematic illustration ofanother guidewire, in a cross-sectional view, generally referenced 220,constructed and operative in accordance with a further embodiment of thedisclosed technique. Guidewire 220 is substantially similar to guidewire100 (FIG. 1A) and includes a distal section 226, a proximal section 228and a set of lines 230 separating the two. Unlike the embodiment of theguidewire shown in FIG. 1A, guidewire 220 is constructed from two hollowtubes of different inner and outer diameters, a thicker hollow tube 224and a thinner hollow tube 222. Thicker hollow tube 224 and thinnerhollow tube 222 can both be hypotubes. In general, thinner hollow tube222 is shorter in length than thicker hollow tube 224. For example,thinner hollow tube 222 may typically measure between 5 and 30centimeters, whereas thicker hollow tube 224 may typically measurebetween 160 and 170 centimeters. As in FIG. 1A, guidewire 220 includes atubular spring 238 and a plug 252, which is placed over the distal endof guidewire 220 in the direction of an arrow 254. Guidewire 220 has alumen 236, where a sensor (not shown) can be placed, and a hollowsection 232, where a twisted pair of wires (not shown) can be placed,which are coupled with the sensor. Guidewire 220 can also be coupledwith an interconnect (not shown). Similar to guidewire 100 (FIG. 1A),guidewire 220 may be also be covered by a thin elastic polymer layer(not shown) over sections 240 and 242.

As in FIG. 1A, guidewire 220 has an initial outer diameter which istapered in distal section 226 to enable the distal section of guidewire220 to have increased flexibility. As shown in FIG. 2, guidewire 220includes a first section 250, which represents the shape of thickerhollow tube 224 over a majority of the length of guidewire 220. In firstsection 250, the dimensions of the guidewire do not change and remainfixed. Adjacent to first section 250 is a first transition section 248,where the outer diameter of thicker hollow tube 224 is gradually tapereduntil a first predetermined reduced outer diameter. Adjacent to firsttransition section 248 and partially overlapping is a second section246, where the dimensions of the guidewire do not change and remainfixed. The second section represents the initial shape of thinner hollowtube 222. Adjacent to second section 246 is a second transition section244, where the outer diameter of thinner hollow tube 222 is graduallytapered until a second predetermined reduced outer diameter. Adjacent tosecond transition section 244 is a third section, which is subdividedinto a floppy section 242 and a sensor housing section 240. This thirdsection is characterized in that the thickness of the walled section ofthinner hollow tube 222 does not change and remains fixed as shown byarrows 260 and 262.

In general, the outer and inner diameters of both thicker hollow tube224 and thinner hollow tube 222 are on the order of hundreds ofmicrometers. For example, the inner and outer diameters of thickerhollow tube 224 may respectfully be 180 μm and 350 μm, whereas the innerand outer diameters of thinner hollow tube 222 may respectfully be 100μm and 180 μm. The inner diameter of thinner hollow tube 222 is shown asan arrow 259. In general, the outer diameter of the thinner hollow tubeis selected such that it is substantially similar to the inner diameterof the thicker hollow tube. In the embodiment shown in FIG. 2, thickerhollow tube 224 is coupled with thinner hollow tube 222 by eitherwelding, bonding or gluing. As shown in FIG. 2, the area which iscoupled between the two hollow tubes is where first transition section248 and second section 246 overlap.

In this embodiment, the initial thickness of the walled section of eachhollow tube, as shown by an arrow 256 and an arrow 258, is reduced andtapered by reducing the outer diameter of the walled section of eachhollow tube. As mentioned above, the outer diameter can be reduced bygrinding or drawing. In one embodiment, the outer diameters of thickerhollow tube 224 and thinner hollow tube 222 are both reduced after theyhave been coupled together. In another embodiment, the outer diametersof thicker hollow tube 224 and thinner hollow tube 222 are both reducedbefore they are coupled together. In a further embodiment, the outerdiameters of thicker hollow tube 224 and thinner hollow tube 222 areboth reduced before they are coupled together and after they are coupledtogether. It is noted that in this embodiment, sensor housing section240 can be formed (i.e., the distal end of guidewire 220 can beenlarged) before tubular spring 238 is placed on floppy section 242.This can be achieved by first enlarging the distal end of guidewire 220before thicker hollow tube 224 and thinner hollow tube 222 are coupledtogether. Once the distal end has been enlarged, tubular spring 238 canbe placed over floppy section 242 and then thicker hollow tube 224 andthinner hollow tube 222 can be coupled together, thereby trappingtubular spring 238 between the larger outer diameters of sensor housingsection 240 and first section 250. In another embodiment, the two hollowtubes can first be coupled together, then tubular spring 238 can beplaced over floppy section 242 and finally, sensor housing section 240can be enlarged to fit the sensor. As mentioned above in conjunctionwith FIG. 1A, the dimensions of the general configuration, as shown inFIG. 2, can be changed and varied so as to provide increasedflexibility, pushability, torque response and tactile feel. For example,more transitions sections could have been present in guidewire 220. Thenumber of transition sections, as well as their respective length can bedetermined and altered by one skilled in the art according to the needsof a particular application, user or both.

Reference is now made to FIG. 3A, which is a perspective illustration ofa guidewire having a tip which exhibits substantially increasedflexibility, generally referenced 280, constructed and operative inaccordance with another embodiment of the disclosed technique. Ingeneral, the flexibility of the hollow tubes illustrated in FIGS. 1A and2 are determined by the thickness of the walled section of eachguidewire near the distal end, as shown by arrows 144 (FIG. 1A) and 146(FIG. 1A) for guidewire 100 (FIG. 1A), and as shown by arrows 260 (FIG.2) and 262 (FIG. 2) for guidewire 220 (FIG. 2). The flexibility is alsodetermined by the inner diameter of each guidewire, as shown by arrow134 (FIG. 1A) for guidewire 100 and by arrow 259 for guidewire 220. Byreducing the thickness of the walled sections of these guidewires nearthe distal end and by reducing the inner diameter, the flexibility ofthese guidewires can be increased. This flexibility is limited by twofactors, the first being the minimal size of the inner diameter of eachguidewire such that a twisted pair of wires can be threaded through. Thesecond is the minimal thickness of the walled section of each guidewiresuch that the general form of the guidewire is maintained and that thewalled section of each guidewire does not break or tear during use. InFIG. 3A, the distal end of guidewire 280 is formed, according to thedisclosed technique, in a manner such that it exhibits increasedflexibility over the flexibility of guidewires 100 and 220. Thus thedistal tip of guidewire 280 exhibits substantial maneuverability.

Guidewire 280 is substantially similar to guidewire 100. Guidewire 280has a distal section 284 and a proximal section 286. Guidewire 280 isconstructed from a hollow tube 282. Guidewire 280 can be coupled with aninterconnect (not shown). Also, guidewire 280 has a sensor (not shown)and a twisted pair of wires (not shown) threaded through the lumen (notshown) of hollow tube 282. The outer diameter of guidewire 280 istapered in distal section 284 and the distal end of guidewire 280 isenlarged to enable the sensor to be placed therein. As in guidewire 100,the inner diameter of hollow tube 282 remains constant along the lengthof the guidewire. Guidewire 280 has a first section 288, where the outerdiameter of the guidewire remains fixed and constant along a majority ofthe length of the guidewire. Adjacent to first section 288 is a floppysection 290, where the outer diameter of guidewire 280 is reduced to apredetermined reduced outer diameter and then kept constant at thepredetermined reduced outer diameter. A tubular spring (not shown) canbe placed around floppy section 290. Adjacent to floppy section 290 is asensor housing section 292 where the sensor is placed. As can be seen inFIG. 3A, sensor housing section 292 is enlarged to enable the sensor tofit in. Similar to guidewire 100 (FIG. 1A), guidewire 280 may be also becovered by a thin elastic polymer layer (not shown) over sections 290and 292.

In guidewire 280, a part of the walled section of hollow tube 282, infloppy section 290, is completely removed, thereby exposing the lumen ofhollow tube 282. This is illustrated in FIG. 3A as an opening 296 and anopening 298. Openings 296 and 298 are located at opposite sides ofhollow tube 282, thereby increasing the flexibility of guidewire 280 ina horizontal plane, as shown by an arrow 299. An area 297 represents thewalled section of hollow tube 282 which is visible once a part of thewalled section in floppy section 290 has been removed. The walledsection removed in floppy section 290 can be removed by either grindingor cutting by laser. Besides removing a part of the walled section infloppy section 290, hollow tube 282 is split in two in a vertical plane,as shown by an arrow 295, from the beginning of sensor housing section292 to substantially the end of floppy section 290. This splittinggenerates two distal ends (i.e., two prongs) in distal section 284, adistal end 300A and a distal end 300B. This is more clearly illustratedin FIG. 3B. It is noted that other embodiments of the construction ofdistal section 284 are possible. For example, instead of removing theupper and lower sides of the walled section of floppy section 290, thelateral sides of the walled section of floppy section 290 can beremoved. In this embodiment, the sensor housing section and the floppysection would be split into two in a horizontal plane.

Once distal section 284 has been constructed as shown in FIG. 3A, thesensor is placed inside an opening 294, and the twisted wire pair,coupled with the sensor, are threaded through the lumen of hollow tube282. Openings 296 and 298 may be filled with a glue to prevent thetwisted pair of wires from moving and being exposed. However, when theglue affects the flexibility of distal section 284, glue may be appliedonly at selected locations along distal section 284 to prevent thetwisted pair of wires from moving. Also distal ends 300A and 300B can beglued to the sensor to keep the sensor in place. A plug (not shown) canbe placed over opening 294 to seal the sensor in. Similar to guidewire100 (FIG. 1A), guidewire 320 may be also be covered by a thin elasticpolymer layer (not shown) over sections 290 and 292.

Reference is now made to FIG. 3B, which is an orthographic illustration,in top view, of the guidewire of FIG. 3A, generally referenced 320,constructed and operative in accordance with a further embodiment of thedisclosed technique. As can be seen in FIG. 3B, guidewire 320 isconstructed from hollow tube 322, which is substantially similar tohollow tube 282 (FIG. 3A). Guidewire 320 has a proximal section 324 anda distal section 326 as well as a first section 332, a floppy section330 and a sensor housing section 328. First section 332, floppy section330 and sensor housing section 328 are respectively substantiallysimilar to first section 288 (FIG. 3A), floppy section 290 (FIG. 3A) andsensor housing section 292 (FIG. 3A). As can be seen from the top viewof FIG. 3B, sensor housing section 328 and floppy section 330 are splitinto two distal ends, a distal end 336A and a distal end 336B. A hollow334 is where a sensor (not shown) is placed, in between distal end 336Aand 336B.

Reference is now made to FIG. 3C, which is an orthographic illustration,in front view, of the guidewire of FIG. 3A, also showing cross-sectionsof the guidewire, generally referenced 350, constructed and operative inaccordance with another embodiment of the disclosed technique. As can beseen in FIG. 3C, guidewire 350 is substantially similar to guidewire280. Guidewire 350 has a proximal section 354 and a distal section 356as well as a first section 366, a first transition section 364, a floppysection 362, a second transition section 360 and a sensor housingsection 358. First section 366, floppy section 362 and sensor housingsection 358 are respectively substantially similar to first section 288(FIG. 3A), floppy section 290 (FIG. 3A) and sensor housing section 292(FIG. 3A). A first transition section and a second transition sectionare shown in both FIGS. 3A and 3B but are not specifically numbered.

In FIG. 3C, dash-dot lines 368 ₁, 368 ₂, 368 ₃, 368 ₄ and 368 ₅represent cut-away cross-sections of guidewire 350. In first section366, a cross-section 370 shows that the hollow tube forming guidewire350 has an initial outer diameter and is completely closed. In firsttransition section 364, the cross-sections 372A and 372B show that theouter diameter has been reduced and that the hollow tube of theguidewire is not completely closed and is split into two sections. Ascan be seen, the outer diameter of cross-sections 372A and 372B issmaller than the outer diameter of cross-section 370. It should be notedthat in first transition section 364, a minority amount of the walledsection of the hollow tube has been completely removed, as thisrepresents the beginning of the area of guidewire 350 where the walledsection of the hollow tube is removed. In floppy section 362, thecross-sections 374A and 374B show that the outer diameter has beenfurther reduced from that of cross-sections 372A and 372B, and that themajority of the walled section of the hollow tube of the guidewire hasbeen completely removed. In second transition section 360, thecross-sections 376A and 376B show that the outer diameter now remainsconstant, as the outer diameter of these cross-sections is substantiallysimilar to the outer diameter as shown in cross-sections 374A and 374B.These cross-sections also show that only a minority of the walledsection of the hollow tube of the guidewire has been completely removed,as this represents the end of the area of guidewire 350 where the walledsection of the hollow tube is removed. In sensor housing section 358,the cross-sections 378A and 378B show that the outer diameter is stillconstant, as the outer diameter of these cross-sections is substantiallysimilar to the outer diameter as shown in cross-sections 374A, 374B,376A and 376B. Also, these cross-sections show that the hollow tube iscut in a vertical plane and split into two sections which are notcoupled (i.e., two prongs).

Reference is now made to FIG. 4, which is a schematic illustrationshowing the procedures executed in forming the guidewire of FIG. 3A,generally referenced 400, constructed and operative in accordance with afurther embodiment of the disclosed technique. In a first procedure 402,a hollow tube 410 having a fixed inner and outer diameter is selected.In a second procedure 404, the outer diameter of a distal section 414 ofa hollow tube 412 is reduced in a step-like, gradual manner. The outerdiameter of a proximal section 416 of hollow tube 412 remains constant.As mentioned above, the outer diameter can be reduced by grinding or bydrawing. In procedure 404, a sub-section 415 of distal section 414 maybe further grounded, or cut by a laser, to completely remove a part ofthe walled section of hollow tube 412 in sub-section 415, as shown asopenings 296 and 298 (both in FIG. 3A) in FIG. 3A. Also, in procedure404, distal section 414 is cut all the way through in a vertical plane,thereby generating two distal ends (not shown).

In a third procedure 406, once the outer diameter of a distal section420 has been reduced and distal section 420 of a hollow tube 418 hasbeen split into two, a tubular spring 422A such as a coil spring isplaced over distal section 420 in the direction of an arrow 424. Thetubular spring is placed over distal section 420 until it is in thelocation of a tubular spring 422B. In a fourth procedure 408, the distalend of a hollow tube 426 is enlarged, for example, by of drawing orpulling hollow tube 426 over a mandrel, or stamping the tip over amandrel between two die sections thereby generating a sensor housingsection 428. Section 428 may further be reinforced by a small section ofthin tube placed there over there by holding the split section. Atubular spring 434 is essentially trapped in a floppy section 430, asthe diameters of a first section 432 and sensor housing section 428 arelarger than the diameter of tubular spring 434. The diameter of sensorhousing section 428, as shown by an arrow 435, which represents the fulldiameter of sensor housing section 428 and not the inner or outerdiameter of that section, is large enough that a tubular spring (notshown) can be inserted. In a fifth procedure 409, once the generalconfiguration of the guidewire has been prepared, a sensor 436, coupledwith a twisted pair of wires 438, referred herein as twisted pair 438,are threaded into the guidewire, in the direction of an arrow 446,through a sensor housing section 442. It is noted that twisted pair 438may be long, as represented by set of lines 440. Once sensor 436 andtwisted pair 438 are threaded through the guidewire, a plug 444 isinserted over the opening of sensor housing section 442 in the directionof an arrow 448. As mentioned above, a sensor 436 may be glued or bondedto the inner sides of sensor housing section 442. Also, the floppysection (not shown) of the guidewire may be covered with a glue to coverany section of twisted pair of wires 438 which are exposed. Twisted pair438 can then be coupled with an interconnect, thereby generating afinished, functional guidewire, substantially similar in configurationto guidewire 280 (FIG. 3A) and in functionality to guidewire 100 (FIG.1A). Additionally, an elastic polymer layer may be applied to the distalend of the guidewire. This elastic polymer layer is typically a heatshrink tube having a thickness in the order of a few microns, whichprovides a slick, smooth, lubricious surface.

Reference is now made to FIG. 5A, which is a perspective illustration ofanother guidewire having a substantially flexible tip, generallyreferenced 470, constructed and operative in accordance with anotherembodiment of the disclosed technique. In FIG. 5A, the distal end ofguidewire 470 is formed, according to the disclosed technique, in amanner such that it exhibits increased flexibility over the flexibilityof guidewires 100 (FIG. 1A) and 220 (FIG. 2). Thus, the distal tip ofguidewire 470 exhibits substantial flexibility, similar to theflexibility of guidewire 280 (FIG. 3A). Guidewire 470 is substantiallysimilar to guidewire 100. Guidewire 470 has a distal section 474 and aproximal section 476. Guidewire 470 is constructed from a hollow tube472. Guidewire 470 can be coupled with an interconnect (not shown).Also, guidewire 470 has a sensor (not shown) and a twisted pair of wires(not shown) threaded through the lumen (not shown) of hollow tube 472.The outer diameter of guidewire 470 is tapered in distal section 474 andthe distal end of guidewire 470 is enlarged to enable the sensor to beplaced therein. As in guidewire 100, the inner diameter of hollow tube472 remains constant along the length of the guidewire. Guidewire 470has a first section 478, where the outer diameter of the guidewireremains fixed and constant along a majority of the length of theguidewire. Adjacent to first section 478 is a floppy section 480, wherethe outer diameter of guidewire 470 is reduced to a predeterminedreduced outer diameter and then kept constant at the predeterminedreduced outer diameter. A tubular spring (not shown) can be placedaround floppy section 480. Adjacent to floppy section 480 is a sensorhousing section 482 where the sensor is placed. As can be seen in FIG.5A, sensor housing section 482 is enlarged to enable the sensor to fitin. Similar to guidewire 100 (FIG. 1A), guidewire 470 may be also becovered by a thin elastic polymer layer (not shown) over sections 488and 488.

In guidewire 470, a part of the walled section of hollow tube 472, infloppy section 480, is completely removed, thereby exposing the lumen ofhollow tube 472. This is illustrated in FIG. 5A as an opening 486. Asopposed to the configuration of guidewire 280 (FIG. 3A), guidewire 470has an opening on only one side of hollow tube 472. Opening 486 islocated on the upper side of hollow tube 472, thereby giving guidewire470 an increase in flexibility in a vertical plane, as shown by an arrow483. An area 487 represents the walled section of hollow tube 472 whichis visible once a part of the walled section in floppy section 480 hasbeen removed. The walled section removed in floppy section 480 can beremoved by either grinding or cutting by laser. Unlike the configurationin FIG. 3A, floppy section 480 and sensor housing section 482 are notsplit into two separate ends. It is noted that other embodiments of theconstruction of distal section 474 are possible. For example, instead ofremoving the upper side of the walled section of floppy section 480, thelateral side or the lower side of the walled section of floppy section480 can be removed. Once distal section 474 has been constructed asshown in FIG. 5A, the sensor is placed inside an opening 484, and thetwisted pair of wires coupled with the sensor are threaded through thelumen of hollow tube 472. Opening 486 can be filled with a glue toprevent the twisted pair of wires from being exposed. A plug (not shown)can be placed over opening 484 to seal in the sensor.

Reference is now made to FIG. 5B, which is an orthographic illustration,in top view, of the guidewire of FIG. 5A, generally referenced 500,constructed and operative in accordance with a further embodiment of thedisclosed technique. As can be seen in FIG. 5B, guidewire 500 isconstructed from hollow tube 502, which is substantially similar tohollow tube 472 (FIG. 5A). Guidewire 500 has a proximal section 504 anda distal section 506 as well as a first section 512, a floppy section510 and a sensor housing section 508. First section 512, floppy section510 and sensor housing section 508 are respectively substantiallysimilar to first section 478 (FIG. 5A), floppy section 480 (FIG. 5A) andsensor housing section 482 (FIG. 5A). As can be seen from the top viewof FIG. 5B, a part of the walled section of floppy section 510 iscompletely removed. Unlike the guidewire shown in FIG. 3B, sensorhousing section 508 is not split into two distal ends. Similar toguidewire 100 (FIG. 1A), guidewire 470 may be also be covered by a thinelastic polymer layer (not shown) over sections 508 and 510.

Reference is now made to FIG. 5C, which is an orthographic illustration,in front view, of the guidewire of FIG. 5A, also showing cross-sectionsof the guidewire, generally referenced 530, constructed and operative inaccordance with another embodiment of the disclosed technique. As can beseen in FIG. 5C, guidewire 530 is substantially similar to guidewire470. Guidewire 530 has a proximal section 534 and a distal section 532as well as a first section 546, a first transition section 544, a floppysection 542, a second transition section 540 and a sensor housingsection 538. First section 546, floppy section 542 and sensor housingsection 538 are respectively substantially similar to first section 478(FIG. 5A), floppy section 480 (FIG. 5A) and sensor housing section 482(FIG. 5A). A first transition section and a second transition sectionare shown in both FIGS. 5A and 5B but are not specifically numbered.

In FIG. 5C, dash-dot lines 548 ₁, 548 ₂, 548 ₃, 548 ₄ and 548 ₅represent cut-away cross-sections of guidewire 530. In first section546, a cross-section 550 shows that the hollow tube forming guidewire530 has an initial outer diameter and is completely closed. In firsttransition section 544, the cross-section 552 shows that the outerdiameter has been reduced and that the hollow tube of the guidewire isnot completely closed. As can be seen, the outer diameter ofcross-section 552 is smaller than the outer diameter of cross-section550. It should be noted that in first transition section 544, a minorityamount of the walled section of the hollow tube has been completelyremoved, as this represents the beginning of the area of guidewire 530where the walled section of the hollow tube is removed. In floppysection 542, the cross-section 554 shows that the outer diameter hasbeen further reduced from that of cross-section 552, and that themajority of the walled section of the hollow tube of the guidewire hasbeen completely removed thereby creating a single prong. In secondtransition section 540, the cross-section 556 shows that the outerdiameter now remains constant, as the outer diameter of thiscross-section is substantially similar to the outer diameter as shown incross-section 554. This cross-section also show that only a minority ofthe walled section of the hollow tube of the guidewire has beencompletely removed, as this represents the end of the area of guidewire530 where the walled section of the hollow tube is removed. In sensorhousing section 538, the cross-section 558 shows that the outer diameteris still constant, as the outer diameter of this cross-section issubstantially similar to the outer diameter as shown in cross-sections556 and 554. Also, this cross-section shows that the hollow tube iscompleted, as in cross-section 550.

Reference is now made to FIG. 6, which is a schematic illustrationshowing the procedures executed in forming the guidewire of FIG. 5A,generally referenced 580, constructed and operative in accordance with afurther embodiment of the disclosed technique. In a first procedure 582,a hollow tube 594 having a fixed inner and outer diameter is selected.In a second procedure 584, the outer diameter of a distal section 598 ofa hollow tube 596 is reduced in a step-like, gradual manner. The outerdiameter of a proximal section 600 of hollow tube 596 remains constant.As mentioned above, the outer diameter can be reduced by grinding or bydrawing. In a third procedure 586, a sub-section 606 of the distalsection may be further grounded, or cut by a laser, to completely removea part of the walled section of a hollow tube 602 in sub-section 606, asshown as opening 486 (FIG. 5A) in FIG. 5A. The area of the distalsection cut out to generate sub-section 606 is shown as a dotted line inprocedure 586. As can be seen, the diameter of sub-section 606 issmaller than the diameter of another sub-section 604.

In a fourth procedure 588, once the outer diameter of a distal section612 has been reduced, a tubular spring 614A is placed over distalsection 612 in the direction of an arrow 616. The tubular spring isplaced over distal section 612 until it is in the location of a tubularspring 614B. In a fifth procedure 590, the distal end of a hollow tube618 is enlarged, thereby generating a sensor housing section 620. Atubular spring 626 is essentially trapped in a floppy section 622, asthe diameters of a first section 624 and sensor housing section 620 arelarger than the diameter of tubular spring 626. The diameter of sensorhousing section 620, as shown by an arrow 628, which represents the fulldiameter of sensor housing section 620 and not the inner or outerdiameter of that section, is large enough that a tubular spring (notshown) can be inserted. In a sixth procedure 592, once the generalconfiguration of the guidewire has been prepared, a sensor 630, coupledwith a twisted pair of wires 632, referred to herein as twisted pair632, are threaded into the guidewire, in the direction of an arrow 640,through a sensor housing section 636. It is noted that twisted pair 632may be long, as represented by set of lines 634. Once sensor 630 andtwisted pair 632 are threaded through the guidewire, a plug 638 isinserted over the opening of sensor housing section 636 in the directionof an arrow 642. As mentioned above, the floppy section (not shown) ofthe guidewire may be covered with a glue to cover any section of twistedpair of wires 632 which are exposed. Twisted pair of wires 632 can thenbe coupled with an interconnect, thereby generating a finished,functional guidewire, substantially similar in configuration toguidewire 470 (FIG. 5A) and in functionality to guidewire 100 (FIG. 1A).Additionally, an elastic polymer layer may be applied to the distal endof the guidewire. This elastic polymer layer is typically a heat shrinktube having a thickness in the order of a few microns, which provides aslick, smooth, lubricious surface.

Reference is now made to FIG. 7, which is a schematic illustration of across sectional view of a guidewire generally referenced 660,constructed and operative in accordance with another embodiment of thedisclosed technique. Guidewire 660 includes a grooved corewire 662, aplug 664, a sensor 666, a twisted pair of wires 668, referred to hereinas twisted pair 668, a tubular proximal end 670 and a tubular spring672. Grooved corewire 662 is made of metal (e.g., stainless steel,nitinol) Sensor 666 is sensor capable of measuring scalar values such aspressure and temperature as well as vector values such as position andorientation of a magnetic field. For example, sensor 66 is a coil sensorcapable of measuring the strength and orientation of a magnetic field.Guidewire 660 can be coupled with an interconnect 674. Twisted pair 668are coupled with sensor 666 and with interconnect 674. Plug 664 iscoupled with the distal tip section 688 of guidewire 660. Tubular spring670 is placed around distal sections 688 and 690 of guidewire 660.Grooved corewire 662 is coupled with tubular proximal end 670 (e.g., bybonding or welding).

In FIG. 7, dash-dot lines 676 ₁, 676 ₂, 676 ₃, 676 ₄ and 676 ₅ representlateral cross-sections of guidewire 660. Along section 694, the diameterof grooved corewire 694 remains substantially constant and is in theorder of hundreds of micrometers. In first cross-section 678, thediameter of grooved corewire 662 has an initial outer diameter and isinserted into tubular proximal end 670. Twisted pair 668 are placedwithin a groove along grooved corewire 662. It is noted that althoughtwisted pair 668 is an unshielded twisted pair, tubular spring 672 mayprovide electrical shielding for twisted pair 668. In secondcross-section 680 the diameter of grooved corewire 662 has an initialouter diameter and twisted pair 668 are placed within a groove alonggrooved corewire 662. However, grooved corewire 662 is no longer withintubular proximal end 670.

Along section 692 of guidewire 660, the diameter of grooved corewire 662is gradually reduced. Furthermore, the shape of the lateralcross-section of grooved corewire 662 gradually changes. In thirdcross-section 682 the shape of the lateral cross-section of groovedcorewire 662 is that of a semi-circle. Furthermore, in thirdcross-section 682, the diameter of grooved corewire 662 is smaller thanin first and second cross-sections 678 and 680. Along section 690, thediameter of grooved corewire 660 is substantially constant, however,this diameter is smaller than the diameter shown in cross-section 682.In forth cross-section 684 the shape of lateral cross-section of groovedcorewire 662 is that of circular segment. Fifth cross-section 686 is across section of the distal tip of guidewire 670 (i.e. section 688).Along section 188 the residual volume between sensor 666 and tubularspring 672 is filled with a polymer bond 665, thus securing the sensorin place. In FIG. 7, the distal end of guidewire 670 is formed,according to the disclosed technique, in a manner such that it exhibitsincreased flexibility over the flexibility of guidewires 100 and 220.Thus the distal tip of guidewire 670 exhibits substantialmaneuverability.

Reference is now made to FIGS. 8A-8E, which are schematic illustrationsof a medical device, such as, for example, a guidewire 750, constructedand operative in accordance with a further embodiment of the disclosedtechnique. While the description below is directed to a guidewire, itwill be appreciated by those having ordinary skill in the art that othermedical devices may also have the same or similar construction, and beconstructed in the same or similar manner. Accordingly, the presentdisclosure is not meant to be limited solely to guidewires, but rather aguidewire is described in detail for exemplary purposes only.

FIG. 8A is a schematic perspective exploded illustration of theguidewire 750. In an exemplary embodiment, guidewire 750 includes acorewire 752, a sensor 753, a sensor core 754 and a coupler 755. Sensor753 is coupled with a sensor core 754 (e.g., the sensor 753 may be woundonto the sensor core 754). The length of sensor core 754 is larger thanthe length of sensor 753. Thus, when sensor 753 is coupled with sensorcore 754, sensor 753 covers only a portion of sensor core 754 such thatsensor core 754 extends from one side of sensor 753. The lengths ofsensor 753 and sensor core 754 are on the order of a few millimeters.For example, in one embodiment, sensor 753 has a length of 1.5 mm, andsensor core 754 has a length of 2 mm. In the illustrated embodiment,sensor 753 is a coil sensor capable of measuring the strength andorientation of a magnetic field. In general, a coil sensor can have athickness on the order of a few hundred micrometers (e.g., 250 μm).

In an exemplary embodiment, corewire 752 is formed of stainless steeland has a proximal end 756 and a distal end 758. In an exemplaryembodiment, corewire 752 has a unitary construction, however, in anotherexemplary embodiment, corewire 752 may be constructed of multiplesegments or pieces that are bonded or otherwise coupled together.Additionally, in an exemplary embodiment, corewire 752 has a constantdiameter from its proximal end 756 to its distal end 758. However, inother exemplary embodiments, the diameter of corewire 752 may vary(e.g., taper) from the proximal end to the distal end thereof. In oneexemplary embodiment, the distal end 758 of corewire 752 exhibitssubstantially the same diameter as sensor core 754 (e.g., on the orderof hundreds of micrometers).

Coupler 755 is a hollow tube with a part of the wall thereof removedalong the length of coupler 755. The inner diameter of coupler 755 issubstantially similar to the diameters of sensor core 754 and the distalend 758 of corewire 752. In an exemplary embodiment, coupler 755 isformed of stainless steel. In other exemplary embodiments, coupler 755may have a construction other than that described above. For example, inanother exemplary embodiment, coupler 755 may have a whole tubeconstruction, and/or may be formed of material(s) other than stainlesssteel. Accordingly, those having ordinary skill in the art willappreciate that guidewires comprising a coupler having a constructionother than a hollow tube with a part of the wall thereof removed andbeing formed of materials other than stainless steel remain within thespirit and scope of the present disclosure.

FIG. 8B is a schematic perspective illustration, and FIG. 8C is aschematic illustration of a cross-sectional view, of guidewire 750 at anintermediate stage of assembly. In FIGS. 8B and 8C, the distal end 758of corewire 752 is inserted into one side of coupler 755. The portion ofsensor core 754 that is not covered by sensor 753 is inserted into theother side of coupler 755. FIG. 8D is a schematic perspectiveillustration of guidewire 750 at a further intermediate stage ofassembly. In FIG. 8D, a twisted pair of wires 759 are electricallyconnected to sensor 753 (e.g., soldered), and mechanically coupled tosensor 753 by a coupling material 760. Twisted pair 759 may be coupledat the proximal end 756 of corewire 752 with an interconnect 761 (bestshown in FIG. 8C) which enables twisted pair 759, and thus sensor 753,to be coupled with other devices, such as a computer, a power source, adevice measuring magnetic field strength and orientation, avisualization, navigation, and/or mapping system, and the like. Inaddition to mechanically coupling the twisted pair 759 to sensor 753,coupling material 760 is also operative to couple sensor core 754 andcorewire 752 with coupler 755. In an exemplary embodiment, couplingmaterial 760 comprises an adhesive, such as, for example and withoutlimitation, epoxy or cyanoacrylate adhesives. It will be appreciated,however, that in other exemplary embodiments, adhesives other than thosespecifically identified above may be used, and therefore, guidewireshaving coupling materials other than epoxy or cyanoacrylate adhesivesremain within the spirit and scope of the present disclosure.

With reference to FIG. 8E, which is a schematic illustration of across-sectional view of guidewire 750 near a final stage of assembly, inan exemplary embodiment, guidewire 750 may further include one or morethin elastic polymer layers 762 disposed over one or more portions ofcorewire 752, sensor 753, sensor core 754, and/or coupler 754. In theexemplary embodiment illustrated in FIG. 8E, polymer layer 762 isdisposed over a portion of corewire 752 near the distal end 758 thereof,and therefore, twisted pair 759. Polymer layer 762 may comprise a heatshrink tube (such as, for example, a hydrophilic tube) of a few micronsthickness, which provides a slick, smooth and lubricious surface. In anembodiment, wherein polymer layer 762 comprises a heat shrink tube, thetube is configured to shrink when exposed to a sufficient amount of heatduring a heating process performed during the assembly of guidewire 750.In an exemplary embodiment, polymer layer 762 may comprise an epoxy,cyanoacrylate, or a ultra-violet (UV) curing adhesive. The presentdisclosure is not meant to be limited to such materials, however, andguidewires having a polymer layer comprising materials other than thosespecifically identified above remain within the spirit and scope of thepresent disclosure.

In an exemplary embodiment, and with continued reference to FIG. 8E,guidewire 750 may further include one or more layers of metallicmaterial 764 disposed over one or more portions of corewire 752, sensor753, sensor core 754, and/or coupler 755. In the exemplary embodimentillustrated in FIG. 8E, guidewire 750 includes one metallic layer 764disposed over a portion of corewire 752 near the distal end 758 thereof,and therefore, twisted pair 759. In an exemplary embodiment, themetallic layer 764 comprises a hypotube formed of, for example,stainless steel, and is coupled to corewire 752. In one embodimentprovided for exemplary purposes only, metallic layer 764 is coupled tocorewire 752 using, for example, an adhesive such as those describedabove. In an exemplary embodiment, metallic layer 764 extends from theproximal end of guidewire 750 to a point at or near the distal endthereof. For example, in the embodiment illustrated in FIG. 8E whereinguidewire 750 includes both polymer layer 762 and metallic layer 764,metallic layer 764 extends from the proximal end of guidewire 750 topolymer layer 762 disposed at or near the distal end of guidewire 750.Accordingly, in such an embodiment, metallic layer 764 is disposedproximate and adjacent to polymer layer 762, and the respective layersmay be bonded or otherwise coupled together using, for example, anadhesive such as those described above.

With continued reference to FIG. 8E, in an exemplary embodiment,guidewire 750 may still further include one or more tubular springs 766covering or circumscribing one or more portions of corewire 752, sensor753, sensor core 754, and/or coupler 755. Tubular spring 766 is a tubeexhibiting lateral flexibility (i.e., perpendicular to the central axisof the tube) made of a metal (e.g., stainless steel, platinum, iridium,nitinol), a flexible polymer tube, or a braided or coiled plastic tube.In an exemplary embodiment, spring 766 comprises a radiopaque materialso as to allow for the visualization of the spring, and therefore, theguidewire 750, when used with an x-ray-based visualization system, suchas, for example, fluoroscopy. Tubular spring 766, which has a length onthe order of centimeters, maintains the outer diameter of guidewire 750over the length thereof, supports compressive loads, and resistsbuckling of the guidewire 750 without substantially increasing torsionaland bending stiffness.

In an exemplary embodiment, spring 766 is rigidly coupled with sensor753. More particularly, one end of spring 766 is bonded to sensor 753.As with the coupling of sensor core 754 and corewire 752 with coupler755, spring 766 may be coupled with sensor 753 with an adhesive, suchas, for example and without limitation, those described above (e.g.,epoxy or cyanoacrylate adhesives). In another exemplary embodiment, andas illustrated in FIG. 8E, rather than coupling one end of spring 766directly to sensor 753, a cylindrical metal shroud 768 covers sensor 753and spring 766 is bonded to shroud 768 using, for example, an adhesivesuch as those described above. In an exemplary embodiment, the end ofspring 766 opposite the end bonded to sensor 753 or shroud 768 iscoupled with polymer layer 762 or metallic layer 763 described aboveusing, for example, an adhesive such as those described above. In anexemplary embodiment, and as illustrated in FIG. 8E, the same type ofadhesive used to bond spring 766 to sensor 753 and/or shroud 766, forexample, may also be used to form a rounded, ball point-type tip at theextreme distal end of the guidewire 750.

In an exemplary embodiment, guidewire 750 may further comprise an outerpolymer layer (not shown) extending from the extreme proximal end to theextreme distal end of guidewire such that substantially the entireassembly is covered with the outer polymer layer. The outer polymerlayer provides added lubricity and hydrophilic properties, and/or formsa substantially smooth external surface of guidewire 750.

Reference is now made to FIGS. 9A and 9B, which are schematicperspective illustrations of a guidewire, generally reference 800,constructed and operative in accordance with a further embodiment of thedisclosed technique. FIG. 9A is a schematic perspective explodedillustration of the guidewire 800. Guidewire 800 includes a firstcorewire 806, a second corewire 808, a sensor 802, a sensor core 804, afirst coupler 810, and a second coupler 812. With respect to at leastfirst corewire 806, sensor 802, sensor core 804, and first coupler 810,the description above relating to the embodiment illustrated in FIGS.8A-8E applies here with equal force, and therefore, will not be repeatedin its entirety.

As illustrated in FIGS. 9A and 9B, sensor 802 is coupled with sensorcore 804 (e.g., the sensor 802 is wound onto the sensor core 804). Thelength of sensor core 804 is larger than the length of sensor 802. Thus,when sensor 802 is coupled with sensor core 804, sensor 802 covers onlya portion of sensor core 804 such that sensor core 804 extends from bothsides of sensor 802. As with the sensor 753 and sensor core 754described above, the lengths of sensor 802 and sensor core 804 are onthe order of a few millimeters. In FIGS. 9A and 9B, sensor 802 is a coilsensor. However, sensor 802 may be any other type of sensor capable ofmeasuring scalar or vector values.

As illustrated in FIG. 9A, at least portions of first and secondcorewires 806 and 808 and sensor core 804 exhibit substantially the samediameter (e.g., on the order of hundreds of micrometers). As withcoupler 755 described above, in an exemplary embodiment, first coupler810 is a hollow tube with a part of the wall thereof removed along thelength of first coupler 810. In an exemplary embodiment, second coupler812 is a whole hollow tube. The inner diameters of first coupler 810 andsecond coupler 812 are substantially similar to the diameters of atleast portions of first and second corewires 806 and 808 and thediameter of sensor core 804. It will be appreciated by those havingordinary skill in the art that in other exemplary embodiments, theconstruction of first and second couplers 810, 812 may be reversed, orboth of couplers 810, 812 may share a common construction (e.g., bothmay be whole tubes, or both may be hollow tubes with parts of the wallsthereof removed along the lengths of the respective couplers).Additionally, in an exemplary embodiment, couplers 810, 812 are formedof stainless steel. However, in other exemplary embodiments, one or bothof couplers 810, 812 may be formed of a material other than stainlesssteel. Accordingly, embodiments of guidewire 800 wherein the first andsecond couplers 810, 812 have a construction other than thoseillustrated in FIGS. 9A and 9B and specifically described above, remainwithin the spirit and scope of the present disclosure.

FIG. 9B is a schematic perspective illustration of guidewire 800 at anintermediate stage of assembly. In FIG. 9B, and as was described abovewith respect to the embodiment illustrated in FIGS. 8A-8E, a twistedpair of wires 814 are electrically connected to sensor 802 (e.g.,soldered) and mechanically coupled to sensor 802 by a coupling material816, such as, for example and without limitation, epoxy or cyanoacrylateadhesives. First corewire 806 is inserted into one side of first coupler810. One side of sensor core 804 is inserted into the other side offirst coupler 810. As was also described above, corewire 806, firstcoupler 810, and sensor core 804 are bonded together by couplingmaterial 816 such as, for example, an epoxy or cyanoacrylate adhesive.The other side of sensor core 804 is inserted into one side of secondcoupler 812. Second corewire 808 is inserted into the other side ofsecond coupler 812. An adhesive, such as, for example and withoutlimitation, an epoxy or cyanoacrylate adhesive, is used to couple thesensor core 804 and the second corewire 808 with the second coupler 812.Thus, rather than the sensor of the guidewire being disposed at thedistal end thereof, in this embodiment, sensor 802 is positionedanywhere along the length of guidewire 800.

As with the embodiment described above with respect to FIGS. 8A-8E,twisted pair 814 may be coupled at the proximal end of guidewire 800with an interconnect (not shown) which enables twisted pair 814, andthus sensor 802, to be coupled with other devices. Additionally, similarto the description above relating to the embodiment illustrated in FIGS.8A-8E, guidewire 800 may include one or more elastic polymer layers,metallic layers, tubular springs, and/or shrouds (not shown) disposedover one or more portions of corewires 806, 808, sensor 802, sensor core804, and or couplers 810, 812. The respective descriptions aboverelating to the composition and arrangement of polymer layer 762,metallic layer 763, tubular spring 766, and shroud 768 apply here withequal force, and therefore, will not be repeated.

Further, in an exemplary embodiment, guidewire 800 may comprise an outerpolymer layer (not shown) extending from the extreme proximal end to theextreme distal end of guidewire such that substantially the entireassembly is covered with the outer polymer layer. The outer polymerlayer provides added lubricity, hydrophilic properties, and/or forms asubstantially smooth external surface of guidewire 800.

With reference to FIG. 10, in addition to the structure of guidewires750, 800, it will be appreciated that another aspect of the presentdisclosure is a method of manufacturing a medical device, such as, forexample, guidewires 750, 800 described above. In an exemplaryembodiment, the method comprises a step 818 of providing a corewire,such as, for example, corewires 752, 806 described above. A step 820comprises providing a sensor core, such as, for example, sensor cores754, 804 described above, configured to have a sensor mounted thereon.The method further comprises a step 822 of providing a coupler, such as,for example, couplers 755, 810 described above, configured to couple thecorewire with the sensor core. In an exemplary embodiment, the methodstill further comprises a step 824 of inserting a portion of the sensorcore into a first end of the sensor core, and a step 826 of inserting aportion of the sensor core into a second end of the coupler. The methodmay further comprise bonding each of the sensor core and the corewire tothe coupler using, for example, adhesives such as those described above.

With continued reference to FIG. 10, in an exemplary embodiment, themethod further comprises a step 828 of mounting a sensor, such as, forexample, sensors 753, 802 described above, onto the sensor core. Themethod may further comprise a step of connecting the sensor to a sensorwire, such as, for example, a twisted pair of wires. In an exemplaryembodiment, the method further comprises a step 830 of covering aportion of at least one of the corewire, coupler, and sensor core withan elastic polymer material, a metallic material, and/or a tubularspring, as described in greater detail above.

In an exemplary embodiment wherein the guidewire comprises a layer ofelastic polymer material, and the polymer material, in turn, comprises aheat shrink material, the method further comprises a step 831 ofapplying heat to the guidewire to cause the polymer material to shrink.

In an exemplary embodiment, the method further comprises steps 832, 834of providing a second corewire, such as, for example, corewire 808described above, and a second coupler, such as, for example, coupler 812described above. In such an embodiment, the method still furthercomprises a step 836 of inserting a second portion of the sensor coreinto a first end of the second coupler, and a step 838 of inserting aportion of the second corewire into a second end of the second coupler.In an exemplary embodiment, the method further comprises bonding thesecond corewire and the sensor core to the second coupler using, forexample, an adhesive such as those described above. In an exemplaryembodiment, the method may still further comprise a step 840 of coveringa least a portion of the second coupler, the sensor core, and the secondcorewire with a polymer material, a metallic material, and/or a tubularspring, such as, for example, the polymer layer, metallic layer, andsprings described above.

In an exemplary embodiment, and whether the guidewire comprises one ortwo corewires or couplers, the method further comprises coveringsubstantially the entire guidewire assembly with a polymer material toform an outer polymer layer.

It will be appreciated that in other exemplary embodiments, themethodology described above may further include steps not specificallydescribed with respect to FIG. 10, but described elsewhere with respectto FIGS. 8A-9B. Accordingly, embodiments of the method comprising suchsteps remain within the spirit and scope of the present disclosure.

Reference is now made to FIGS. 11A and 11B, which are schematicperspective illustrations of a guidewire 900 constructed and operativein accordance with yet another embodiment of the present disclosure.While the description below is directed to a guidewire, it will beappreciated by those having ordinary skill in the art that other medicaldevices may also have the same or similar construction, and beconstructed in the same or similar manner. Accordingly, the presentdisclosure is not meant to be limited solely to guidewires, but rather aguidewire is described for exemplary purposes only.

FIG. 11A is a schematic perspective exploded illustration of theguidewire 900. The guidewire 900 comprises a corewire 902 and a sensorassembly 904. Corewire 902, which may be constructed of, for example andwithout limitation, stainless steel, has a proximal end 906 and a distalend 908. In an exemplary embodiment, corewire 902 has a unitaryconstruction, however, in another exemplary embodiment, corewire 902 maybe constructed of multiple segments or pieces that are bonded orotherwise coupled together. Whether formed of one or multiple segmentsor pieces, in an exemplary embodiment corewire 902 comprises twoportions. A first portion 910 extends from proximal end 906 to a pointnear distal end 908. In an exemplary embodiment, first portion 910 ofcorewire 902 tapers from proximal end 906 thereof to a point near distalend 908. In an exemplary embodiment, the diameter (i.e., diameter 912)near the end of first portion 910 is on the order of 0.1-0.2 mm. Asecond portion 914 of corewire 902 extends from the distal end point offirst portion 910 to the most distal point of corewire 902 at distal end908. Second portion 914 has a diameter 916 that is less than diameter912 of first portion 910. In one embodiment provided for exemplarypurposes only, diameter 912 is on the order of 0.05-0.08 mm. As will bedescribed in greater detail below, second portion 914 of corewire 902 isconfigured to be coupled with sensor assembly 904.

With continued reference to FIG. 11A, in an exemplary embodiment, sensorassembly 904 comprises a sensor core 918 and a sensor 920 mounted onsensor core 918. Sensor core 918 has a first end 922 and a second end924, and defines a longitudinal axis 926 extending through both firstand second ends 922, 924. In an exemplary embodiment, sensor core 918 isconstructed of a metallic material that displays high ferromagneticproperties (e.g., iron, nickel, alloys, and the like). Additionally, inan exemplary embodiment, sensor core 918 has an outer diameter that issubstantially equal to diameter 912 of first portion 910 of corewire 902(e.g., on the order of 0.1-0.2 mm). As illustrated in FIG. 11A, thelength of sensor core 918 is larger than that of sensor 920. Thus, whensensor 920 is coupled with sensor core 918, sensor 920 covers only aportion of sensor core 918 such that sensor core 918 extends from one orboth sides of sensor 920 at first and/or second ends 922, 924 of sensorcore 918.

Sensor core 918 includes a bore 928 disposed within first end 922thereof along longitudinal axis 926. In an exemplary embodiment, bore928 is a closed bore (i.e., bore 928 does not extend from first end 922of sensor core 918 through second end 924 thereof). In such anembodiment, bore 928 may have a depth on the order of, for example andwithout limitation, 0.1-0.3 mm. In another exemplary embodiment,however, bore 928 is a through bore extending from first end 922 ofsensor core 918 through second end 924. Bore 928 may be formed byperforming a drilling operation on first end 922 of sensor core 918, orit may be formed during the construction of sensor core 918. In anyevent, bore 928 is sized and configured to receive second portion 914 ofcorewire 902. Therefore, bore 928 has a diameter that is substantiallysimilar to diameter 916 of the second portion 914 of the corewire 902(e.g., on the order of 0.05-0.08 mm). Accordingly, when assembled, andas illustrated in FIG. 11B, second portion 914 of corewire 902 isdisposed within bore 928 of sensor core 918. In an exemplary embodiment,second portion 914 of corewire 902 is bonded to sensor core 918 by anadhesive such as, for example, epoxy or cyanoacrylate adhesivesdescribed above.

It will be appreciated that while in the illustrated embodiment areduced diameter portion of corewire 902 is configured to be insertedinto and disposed within bore 928 of sensor core 918, in anotherexemplary embodiment, corewire 902 does not have a defined reduceddiameter portion at distal end 908 thereof, but rather corewire 902 hasa uniform diameter throughout, or tapers from proximal end 906 to distalend 908. In such an embodiment, bore 928 in sensor core 918 would besized so as to receive distal end 908 of corewire 902. Accordingly, inany embodiment, bore 928 is sized so as to receive the extreme distalend 908 of corewire 902, regardless of whether it has the same ordifferent diameter as the rest of corewire 902.

With reference to FIG. 11C, and as with the embodiment described abovewith respect to FIGS. 9A and 9B, in an exemplary embodiment, guidewire900 may include a second corewire 930 coupled with sensor core 918. Insuch an embodiment, bore 928 would extend through core 918 from firstend 922 to second end 924, or sensor core 918 would include a secondbore in second end 922 of the sensor core 918. In either embodiment, oneend of second corewire 930 would have a diameter that is substantiallysimilar to that of the bore in second end 922 of sensor core 918 suchthat a portion of corewire 930 could be inserted into the bore.Accordingly, the second corewire 930 may have a reduced diameter portion(similar to that of corewire 908), or may simply have a diameter sizedso as to allow for corewire 930 to be inserted into the bore. As wasdescribed in great detail above with respect to corewire 902, in anexemplary embodiment, corewire 930 is bonded to sensor core 918 by anadhesive, such as, for example, epoxy or cyanoacrylate adhesives.

Whether guidewire 900 has one or two corewires, it may have anadditional sensor and sensor core attached thereto in the mannerdescribed herein. For example, a first sensor core 918 may have athrough bore 928 therein that corewire 902 passes through, to wheresecond portion 916 of corewire 902 then is inserted into bore 928′ (notshown) of a second sensor core 918′ (not shown). Both sensor cores 918,918′ would then have sensors 920, 920′, respectively, affixed thereto.Likewise, corewire 902 may be joined to a first sensor core 918 as shownin FIG. 11A at bore 928, with a second corewire 930 joined at itsproximal end to the distal end of sensor core 918. The second corewire930 is then joined at its distal end to a bore 928′ (not shown) of asecond sensor core 918′ (not shown).

With reference to FIGS. 11B and 11C, whether the guidewire 900 has oneor two corewires, sensor assembly 904 includes a sensor 920 mounted onsensor core 918. In one embodiment provided for exemplary purposes only,sensor 920 comprises an electromagnetic field detector. In such anembodiment, sensor 920 comprises an electromagnetic coil wound aroundsensor core 918. In one embodiment provided for exemplary purposes only,sensor 920 has a length on the order of 1-2 mm, and an outer diameter onthe order of 0.25 mm. While sensor 920 has been described above ascomprising an electromagnetic field detector, it will be appreciated bythose having ordinary skill in the art that in other exemplaryembodiments, sensors other than electromagnetic field detectors may bemounted on sensor core 918. Therefore, a sensor comprising anelectromagnetic field detector is described for exemplary purposes onlyand is not meant to be limiting in nature.

Whether sensor 920 comprises an electromagnetic field detector orotherwise, sensor 920 may be electrically connected (e.g., soldered) toa twisted pair of wires 931. Twisted pair 931 may extend the length ofcorewire 902 from sensor 920 at distal end 908 thereof, to proximal end906. In such an embodiment, twisted pair 931 may be electricallyconnected to an interconnect 932, thereby enabling twisted pair 931, andthus sensor 920, to be coupled with other devices, such as, for exampleand without limitation, a computer, a power source, a device measuringmagnetic field strength and orientation, a visualization, navigation,and/or mapping system, and the like.

With reference to FIG. 11D, which is a schematic illustration of across-sectional view of guidewire 900 near a final stage of assembly, inan exemplary embodiment, guidewire 900 may further include one or morethin elastic polymer layers 934 disposed over one or more portions ofcorewire 902, sensor 920, and/or sensor core 918. In the exemplaryembodiment illustrated in FIG. 11D, polymer layer 934 is disposed over aportion of corewire 902, and therefore, twisted pair 931. Polymer layer934 may comprise a heat shrink tube (such as, for example, a hydrophilictube) of a few microns thickness, which provides a slick, smooth andlubricious surface. In an embodiment, wherein polymer layer 934comprises a heat shrink tube, the tube is configured to shrink whenexposed to a sufficient amount of heat during a heating processperformed during the assembly of guidewire 900. In an exemplaryembodiment, polymer layer 934 may comprise an epoxy, cyanoacrylate, or aultra-violet (UV) curing adhesive. The present disclosure is not meantto be limited to such materials, however, and guidewires having apolymer layer comprising materials other than those specificallyidentified above remain within the spirit and scope of the presentdisclosure.

In an exemplary embodiment, and with continued reference to FIG. 11D,guidewire 900 may further include one or more layers of metallicmaterial 936 disposed over one or more portions of corewire 902, sensor920, and/or sensor core 918. In the exemplary embodiment illustrated inFIG. 11D, guidewire 900 includes one metallic layer 936 disposed over aportion of corewire 902, and therefore, twisted pair 931. In anexemplary embodiment, the metallic layer 936 comprises a hypotube formedof, for example, stainless steel, and is coupled to corewire 902. In oneembodiment provided for exemplary purposes only, metallic layer 936 isbonded to corewire 902 using, for example, an adhesive such as thosedescribed above. In an exemplary embodiment, metallic layer 936 extendsfrom the proximal end of guidewire 900 to a point at or near the distalend thereof. For example, in the embodiment illustrated in FIG. 11Dwherein guidewire 900 includes both polymer layer 934 and metallic layer936, metallic layer 936 extends from the proximal end of guidewire 900to polymer layer 934 disposed at or near the distal end of guidewire900. Accordingly, in such an embodiment, metallic layer 936 is disposedproximate and adjacent to polymer layer 934, and the respective layersmay be bonded or otherwise coupled together using, for example, anadhesive such as those described above.

With continued reference to FIG. 11D, in an exemplary embodiment,guidewire 900 may still further include one or more tubular springs 938covering or circumscribing one or more portions of corewire 902, sensor920, and/or sensor core 918. Tubular spring 938 is a tube exhibitinglateral flexibility (i.e., perpendicular to the central axis of thetube) made of a metal (e.g., stainless steel, platinum, iridium,nitinol), a flexible polymer tube, or a braided or coiled plastic tube.In an exemplary embodiment, spring 938 comprises a radiopaque materialso as to allow for the visualization of the spring, and therefore, theguidewire 900, when used with an x-ray-based visualization system, suchas, for example, fluoroscopy. Tubular spring 938, which has a length onthe order of centimeters, maintains the outer diameter of guidewire 900over the length thereof, supports compressive loads, and resistsbuckling of the guidewire 900 without substantially increasing torsionaland bending stiffness.

In an exemplary embodiment, spring 938 is rigidly coupled with sensor920. More particularly, one end of spring 938 is bonded to sensor 920.As with the coupling of sensor core 918 and corewire 902, spring 938 maybe coupled with sensor 920 with an adhesive, such as, for example andwithout limitation, those described above (e.g., epoxy or cyanoacrylateadhesives). In another exemplary embodiment, and as illustrated in FIG.11D, rather than coupling one end of spring 938 directly to sensor 920,a cylindrical metal shroud 940 covers sensor 920 and spring 938 isbonded to shroud 940 using, for example, an adhesive such as thosedescribed above. In an exemplary embodiment, the end of spring 938opposite the end bonded to sensor 920 or shroud 940 is coupled withpolymer layer 934 or metallic layer 936 described above using, forexample, an adhesive such as those described above. In an exemplaryembodiment, and as illustrated in FIG. 11D, the same type of adhesiveused to bond spring 938 to sensor 920 or shroud 940, for example, mayalso be used to form a rounded, ball point-type tip at the extremedistal end of the guidewire 900.

In an exemplary embodiment, guidewire 900 may further comprise an outerpolymer layer (not shown) extending from the extreme proximal end to theextreme distal end of guidewire such that substantially the entireassembly is covered with the outer polymer layer. The outer polymerlayer provides added lubricity and hydrophilic properties, and/or formsa substantially smooth external surface of guidewire 900.

In addition to the structure of guidewire 900, it will be appreciatedthat another aspect of the present disclosure is a method ofmanufacturing a medical device, such as, for example, guidewire 900.With reference to FIGS. 11A-12, in a exemplary embodiment, the methodcomprises a step 942 of providing a sensor core, such as, for example,sensor core 918 described above. The method further comprises a step 944of providing a corewire, such as, for example, corewire 902 describedabove. The method still further comprises a step 946 of forming a bore,such as, for example, bore 928 described above, in a first end of sensorcore 918. In another exemplary embodiment, both ends of the sensor corehave a bore therein. In one embodiment, the bore is a through boreextending all the way through the core from the first end through thesecond end. Alternatively, each end of the sensor core has anindependent bore formed therein.

The method yet still further comprises a step 948 of inserting a portionof corewire into the bore in the sensor core. The method may furthercomprise bonding the corewire with the sensor core using an adhesivesuch as those described above. In an exemplary embodiment, the methodfurther comprises a step 950 of mounting a sensor, such as, for example,sensor 920 described above, onto the sensor core. In an exemplaryembodiment, step 950 may comprise winding a sensor coil onto the sensorcore. It will be appreciated by those having ordinary skill in the art,however, that in other exemplary embodiments, the sensor may be mountedto the sensor core using other techniques known in the art. Accordingly,embodiments of the method wherein the sensor is mounted to the sensorcore using techniques other than those described with particularityherein, remain within the spirit and scope of the present disclosure. Inany embodiment, the method may further comprise a step of connecting asensor wire, such as, for example, a twisted pair of wires, to thesensor.

In an exemplary embodiment, the method further comprises a step 952 ofcovering a portion of at least one of the corewire, coupler, and sensorcore with an elastic polymer material, a metallic material, and/or atubular spring, as described in greater detail above.

In an exemplary embodiment wherein the guidewire comprises a layer ofelastic polymer material, and the polymer material, in turn, comprises aheat shrink material, the method further comprises a step 954 ofapplying heat to the guidewire to cause the polymer material to shrink.

In an exemplary embodiment, the method further comprises step 956 ofproviding a second corewire, such as, for example, corewire 930described above. In such an embodiment, the method still furthercomprises a step 958 of inserting a portion of corewire 930 into a borein the second end of the sensor core. In an exemplary embodiment, themethod may further include applying an adhesive to one or both of thecorewire 930 and the inner surface of the bore to bond the corewire tothe sensor core, as described above. In an exemplary embodiment, themethod may still further comprise a step 960 of covering a least aportion of the sensor, sensor core, and/or second corewire with apolymer material, a metallic material, and/or a tubular spring, such as,for example, the polymer layer, metallic layer, and springs describedabove.

In an exemplary embodiment, and whether the guidewire comprises one ortwo corewires, the method further comprises covering substantially theentire guidewire assembly with a polymer material to form an outerpolymer layer.

It will be appreciated that in other exemplary embodiments, themethodology described above may further include steps not specificallydescribed with respect to FIG. 12, but described elsewhere with respectto FIGS. 11A-11C. Accordingly, embodiments of the method comprising suchsteps remain within the spirit and scope of the present disclosure.

Although only certain embodiments have been described above with acertain degree of particularity, those skilled in the art could makenumerous alterations to the disclosed embodiments without departing fromthe scope of this disclosure. Joinder references (e.g., attached,bonded, coupled, connected, and the like) are to be construed broadlyand may include intermediate members between a connection of elementsand relative movement between elements. As such, joinder references donot necessarily infer that two elements are directly connected/coupledand in fixed relation to each other. It is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative only and not limiting. Changes indetail or structure may be made without departing from the invention asdefined in the appended claims.

The invention claimed is:
 1. A medical device, comprising: a corewirehaving a proximal end and a distal end, said distal end terminating at adistal tip; a sensor assembly comprising a sensor core and a sensor; oneor more wires electrically coupled with the sensor; and an electricalinterconnect, disposed at said corewire proximal end, configured to beelectrically coupled with said one or more wires to provide anelectrical connection between said sensor and an external device;wherein said sensor core comprises a proximal end, a distal end, and abore in said proximal end, and further wherein said corewire distal tipis disposed within said bore in said sensor core, further wherein saidcorewire proximal end is proximal of said sensor core proximal endfurther wherein said sensor core defines a longitudinal axis extendingfrom said sensor core proximal end to said sensor core distal end andsaid sensor core has a radially-outermost surface, said sensor mountedon said radially-outermost surface.
 2. The medical device of claim 1,wherein said corewire includes a first portion having a first diameterand a second portion located at said distal end having a second diameterthat is less than said first diameter, and further wherein said distaltip is a part of said second portion of said corewire.
 3. The medicaldevice of claim 1, wherein said sensor comprises an electromagneticfield detector comprising a coil wound on said sensor core.
 4. Themedical device of claim 1, further comprising at least one of a polymerlayer, a metallic layer, and a tubular spring covering at least aportion of at least one of said sensor core and said corewire.
 5. Amethod of manufacturing a medical device, the method comprising:providing a sensor core configured to have a sensor mounted on saidsensor core, said sensor core defining a longitudinal axis extendingfrom a proximal end to a distal end, said sensor core having aradially-outermost surface; providing a corewire having a proximal endand a distal end, said distal end terminating in a distal tip; mountinga sensor onto said radially-outermost surface of said sensor core;forming a bore in said proximal end of said sensor core; and inserting aportion of said corewire into said bore; and rigidly coupling saidcorewire with said sensor core with said distal tip of said corewiredisposed in said bore.
 6. The method of claim 5, wherein said forming abore comprises drilling said bore into said first end of said sensorcore.
 7. The method of claim 5, further comprising covering at least aportion of at least one of said corewire and said sensor core with atleast one of an elastic polymer material, a metallic material, and atubular spring.
 8. The method of claim 7, wherein said polymer materialcomprises a heat shrink tube, said method further comprising the step ofapplying heat to said polymer material.
 9. The method of claim 5,wherein said corewire is a first corewire, and said forming a borefurther comprises forming a bore in said distal end of said sensor core,said method further comprising: providing a second corewire; andinserting said second corewire into said bore in said distal end of saidsensor core such that a proximal end of said second corewire is disposedin said bore in said distal end of said sensor core.
 10. The method ofclaim 9, wherein said bore in said sensor core proximal end iscontinuous with said bore in said sensor core distal end.
 11. A medicaldevice, comprising: a non-hollow corewire having a proximal end and adistal end, said proximal end terminating in a proximal tip and saiddistal end terminating in a distal tip; a sensor assembly comprising asensor core and a sensor; and at least one of a polymer layer, ametallic layer, and a tubular spring covering at least a portion of atleast one of said sensor core and said corewire; wherein said sensorcore comprises a first end, a second end, and a bore in said first end,and further wherein one of said corewire distal tip and said corewireproximal tip is disposed within said bore in said sensor core, furtherwherein said sensor core defines a longitudinal axis extending from saidfirst end to said second end and said sensor core has aradially-outermost surface, said sensor mounted on saidradially-outermost surface.
 12. The medical device of claim 11, whereinsaid corewire includes a first portion having a first diameter and asecond portion located at said distal end having a second diameter thatis less than said first diameter, and further wherein said distal tip isa part of said second portion of said corewire.
 13. The medical deviceof claim 11, wherein said sensor comprises an electromagnetic fielddetector comprising a coil wound on said sensor core.
 14. The medicaldevice of claim 11, wherein said corewire is cylindrical.
 15. Themedical device of claim 11, wherein said corewire is a first corewire,and said sensor core further comprises a bore in said second end, themedical device further comprising a second non-hollow corewirecomprising a proximal end and a distal end, one of said second corewireproximal end and said second corewire distal end disposed within saidbore in said second end of said sensor core.
 16. The medical device ofclaim 15, wherein said bore in said sensor core first end is continuouswith said bore in said sensor core second end.
 17. The medical device ofclaim 15, wherein said bore in said sensor core first end is notcontinuous with said bore in said sensor core second end.
 18. Themedical device of claim 15, wherein said first corewire and said secondcorewire are cylindrical.
 19. A medical device, comprising: a non-hollowcorewire having a proximal end and a distal end; and a sensor assemblycomprising a sensor core and a sensor; wherein said sensor corecomprises a first end, a second end, and a bore in said first end, andfurther wherein one of said corewire distal end and said corewireproximal end is disposed within said bore in said sensor core, furtherwherein said sensor core defines a longitudinal axis extending from saidfirst end to said second end and said sensor core has aradially-outermost surface, said sensor mounted on saidradially-outermost surface; wherein one of said corewire distal end andsaid corewire proximal end is bonded to said sensor core with adhesive.20. The medical device of claim 19, wherein said corewire is a firstcorewire, said bore is a blind bore, and said sensor core furthercomprises a blind bore in said second end, the medical device furthercomprising a second non-hollow corewire comprising a proximal end and adistal end, one of said second corewire proximal end and said secondcorewire distal end disposed within said blind bore in said second endof said sensor core, said blind bore in said first end of said sensorcore not being continuous with said blind bore in said second end ofsaid sensor core.
 21. The medical device of claim 19, wherein saidcorewire includes a first portion having a first diameter and a secondportion located at said distal end having a second diameter that is lessthan said first diameter, and further wherein said second portion ofsaid corewire is disposed within said bore in said sensor core.
 22. Themedical device of claim 19, wherein said corewire is cylindrical. 23.The medical device of claim 1, wherein said interconnect is electricallycoupled with said one or more wires.